Pfc. David Lawrence faces a military hearing in Ft. Carson, Colo. His parents and attorney say he showed signs of mental instability before last month's slaying in Kandahar.

Reporting from San Diego — The military equivalent of a preliminary hearing is set for Monday at Ft. Carson, Colo., for an Army private accused of premeditated murder in the shooting death of a senior Taliban commander being held prisoner in Afghanistan.

Pfc. David W. Lawrence, 20, is accused of shooting Mullah Mohebullah in the head Oct. 17 while assigned to guard duty at a detention center in the Arghandab district of Kandahar province.

Under military law, premeditated murder can carry the death penalty.

The death was announced by an angry Afghan President Hamid Karzai, who vowed to launch his own investigation. Karzai has repeatedly criticized NATO forces for what he has termed a wanton use of deadly force.

The case sits at the intersection of two of the more controversial aspects of the war: the testy relationship between the U.S. and Karzai, and the military's treatment of soldiers who show signs of mental instability while in the war zone.

In the days before the shooting, Lawrence had been seen by medical personnel at Kandahar and given drugs for depression and sleeplessness, his attorneys said. Shortly afterward, Lawrence was assigned to guard duty, a task for which he had no training.

Lawrence's parents, Brett and Wendy Lawrence, said that their son had told them repeatedly in e-mail messages and phone calls that he was hearing voices, including one that told him how to avoid the buried roadside bombs that are the top killer of NATO and Afghan troops.

"He said those voices were guiding him and telling him what to do," Wendy Lawrence said.

The stress and danger of Kandahar, a major battleground between the U.S. and Taliban fighters, was causing Lawrence's mental state to deteriorate, his parents said.

"He said it was the worst place on earth," said Brett Lawrence, a hospital employee in Lawrenceburg, Ind.

Wendy Lawrence said several of her relatives had mental illnesses including paranoia and schizophrenia. David is her son from a previous marriage.

The Army has ordered a sanity board investigation. Lawrence's civilian lawyer, James Culp, was denied a request to delay the preliminary hearing, called an Article 32, until the sanity board reached its conclusions.

"We are going to an Article 32 for a kid who is hearing voices," Culp said. He said he was concerned the Army might be rushing the case to court-martial to appease Karzai.

Rather than hold the Article 32 in Afghanistan, the Army decided to bring Lawrence to Ft. Carson.

"He seemed like he was heavily sedated," said Brett Lawrence, who was allowed to see his son. "He didn't seem like he's seeing reality."

His son told him that he was seeing soldiers who had died in Afghanistan, including Capt. Dale Goetz, a chaplain. "He said he could see the chaplain with only half a head remaining," Brett Lawrence said.

The young soldier had become friends with the charismatic chaplain at Ft. Carson before their deployment and remained in contact with him in Afghanistan.

Goetz was among five U.S. soldiers killed Aug. 30 when their vehicle hit a roadside bomb outside Kandahar. He was the first chaplain killed in combat in 40 years, the Army said.

Lawrence had spoken of Goetz to his parents in glowing terms. They feel Goetz's death may have exacerbated their son's mental problems.

Lawrence, who has been examined by doctors at Landstuhl Regional Medical Center in Germany and Walter Reed Army Medical Center in Washington, is restricted to his barracks at Ft. Carson.

Lawrence left high school at 17 to join the Indiana National Guard and later transferred to the active-duty Army. He liked to fish, ride his motorcycle and play computer games but was not much of a student.

"We thought he wanted to better his life and make a career out of the Guard and the Army," Wendy Lawrence said.

He had been in Afghanistan, his first deployment, for four months when the prisoner was killed. Prior to his guard duty assignment, he was part of a security detail for the battalion commander, which meant repeated missions "outside the wire" and exposure to the threat of snipers and roadside bombs.

Under military rules, the Article 32 hearing officer will recommend to the senior officer acting as convening authority whether the case should go to a court-martial, be dismissed or be dealt with through an administrative procedure.

Culp, a lawyer based in Austin, Texas, has defended several military personnel accused of crimes in Iraq and Afghanistan. He asked that the Article 32 hearing be delayed until he could go to Afghanistan to see the crime scene and meet with a soldier who may have witnessed the killing. His request was denied.

The Lawrence family is preparing for what may be a long and costly legal fight.